Featured Research

Hypothyroidism During Pregnancy Linked To Lower IQ For Child

Date:

August 23, 1999

Source:

NIH-National Institute Of Child Health And Human Development

Summary:

Children born to mothers with untreated hypothyroidism during pregnancy score lower on IQ tests than children of healthy mothers, according to a study conducted by Dr. James Haddow and partially funded by the National Institute of Child Health and Human Development.

Share This

Children born to mothers with untreated hypothyroidism during pregnancy score lower on IQ tests than children of healthy mothers, according to a study conducted by Dr. James Haddow and partially funded by the National Institute of Child Health and Human Development (NICHD) and reported in the August 19 issue of the New England Journal of Medicine. However, children whose mothers were being treated for the condition scored almost the same as children born to healthy mothers. These findings suggest that early detection and treatment of hypothyroidism in pregnant women may be a critical part of prenatal care.

Related Articles

"We know that the health of the mother can be a key factor in her baby's health," said Duane Alexander, M.D., Director of the NICHD. "Fortunately, hypothyroidism is a condition that can be identified and treated during pregnancy. This study suggests that hypothyroidism might be added to the group of correctable maternal conditions that can influence the long-term health of the child," he said.

From 25,216 frozen serum samples obtained during pregnancy, researchers identified 62 women who had children between January 1987 and March 1990 and who, in retrospective analysis, were identified as having been hypothyroid during their pregnancies. These children were compared to a carefully matched group of 124 control children whose mothers' thyroid function in pregnancy was normal.

At the time of the study, the children ranged in age from 7 to 9 years. They participated in a series of 15 psychological tests relating to intelligence, attention, language, reading and school problems, and visual-motor performance.

The children born to mothers who were hypothyroid during pregnancy scored an average of 4 points lower in IQ tests than the control children, and 15 percent had IQ scores lower than 85, compared to only 5 percent of the control children who scored that low. Overall, the case children scored poorer on all 15 individual tests than the children born to healthy mothers.

Of the 62 women with hypothyroidism, 48 did not receive treatment during pregnancy for their condition. Their children's IQ scores averaged 7 points lower than children of mothers without the condition, and 19 percent had IQ scores below 85. However, the children born to mothers who were receiving treatment scored similarly to the control children, suggesting that treatment can help mitigate the adverse effects.

"These findings suggest that early detection and treatment for hypothyroidism of the mother during pregnancy might be an important factor in the intelligence and well-being of her child," said James E. Haddow, M.D., lead author of the study. "However, these data do not allow us to determine whether detection and treatment must be accomplished prior to the pregnancy to be effective, or whether they will be effective if done early in pregnancy."

The thyroid gland is found in the neck and produces a hormone instrumental to many bodily functions. Hypothyroidism is a condition where the gland does not produce enough hormone. Signs and symptoms of hypothyroidism include feeling tired or without energy; coarse, brittle hair; thick, coarse skin; and a lowering of the metabolic rate.

Studies indicate that over a 10-year period, about 3% of women of childbearing age will develop the condition. However, in many women, hypothyroidism goes undetected because they do not yet have obvious physical signs or symptoms. Only 14 of the 62 women with hypothyroidism in this study had the condition detected and treated before their pregnancies, and on average the remaining women did not find out until 5 years after their pregnancies.

Doctors can find out if a woman has hypothyroidism by performing a blood test to measure levels of thyroid stimulating hormone (TSH), also known as serum thyrotropin. High TSH levels serve as an early warning system that the thyroid is not functioning adequately. The condition can then be treated with medication (thyroid hormone).

"There is an opportunity when women are pregnant and going for prenatal care to get a routine TSH test. It is a simple test for a condition with easy treatment. By taking action early, we might be able to help prevent adverse consequences to the child and the mother," said Haddow.

IQ Scores in Children with Healthy Mothers Compared to IQ Scores in Children Whose Mothers Were Hypothyroid During Pregnancy

More From ScienceDaily

More Health & Medicine News

Featured Research

Mar. 3, 2015 — Scientists have discovered a new hormone that fights the weight gain caused by a high-fat Western diet and normalizes the metabolism -- effects commonly associated with exercising. When tested in ... full story

Mar. 3, 2015 — New assays can detect malaria parasites in human blood at very low levels and might be helpful in the campaign to eradicate malaria, reports a new study. An international team led by Ingrid Felger, ... full story

Mar. 3, 2015 — Adults over the age of 30 only catch flu about twice a decade, a new study suggests. So, while it may feel like more, flu-like illness can be caused by many pathogens, making it difficult to assess ... full story

Mar. 3, 2015 — No significant change in home habits of smokers have been observed in the aftermath of a ban on smoking in public spaces, researchers report. Greater inspiration to kick the habit likely comes from ... full story

Mar. 3, 2015 — Heart function has been associated with the development of dementia and Alzheimer's disease through a new study. Participants with decreased heart function, measured by cardiac index, were two to ... full story

Mar. 3, 2015 — Children of recently separated or divorced families are likelier to drink sugar-sweetened beverages than children in families where the parents are married, putting them at higher risk for obesity ... full story

Mar. 3, 2015 — Gastric bypass and similar stomach-shrinking surgeries are a popular option for obese patients looking to lose weight or treat type 2 diabetes. While the surgeries have been linked to a decreased ... full story

Mar. 3, 2015 — Most people consume more salt than they need and therefore have a higher risk of heart disease and stroke, which are the two leading causes of death worldwide. But a new study reveals that dietary ... full story

Featured Videos

Mom Triumphs Over Tragedy, Helps Other Families

AP (Mar. 3, 2015) — After her son, Dax, died from a rare form of leukemia, Julie Locke decided to give back to the doctors at St. Jude Children&apos;s Research Hospital who tried to save his life. She raised $1.6M to help other patients and their families. (March 3)
Video provided by AP

Looted and Leaking, South Sudan's Oil Wells Pose Health Risk

AFP (Mar. 3, 2015) — Thick black puddles and a looted, leaking ruin are all that remain of the Thar Jath oil treatment facility, once a crucial part of South Sudan&apos;s mainstay industry. Duration: 01:13
Video provided by AFP

Woman Convicted of Poisoning Son

AP (Mar. 3, 2015) — A woman who blogged for years about her son&apos;s constant health woes was convicted Monday of poisoning him to death by force-feeding heavy concentrations of sodium through his stomach tube. (March 3)
Video provided by AP

Related Stories

Feb. 3, 2015 — Children of mothers who smoke while breast feeding are more likely to develop serious health problems such as obesity, hypothyroidism, diabetes and cardiovascular disease later in life, according to ... full story

Feb. 2, 2015 — Pregnancy outcomes appear to be similar for women who undergo kidney transplants as children or adults, according to an article. Previous studies have reported pregnancy outcomes for women with ... full story

July 26, 2012 — Congenital hypothyroidism is thyroid hormone deficiency at birth that, if left untreated, can lead to neurocognitive impairments in infants and children. Although the World Health Organization ... full story

July 26, 2011 — Children born after unplanned pregnancies tend to have a more limited vocabulary and poorer non-verbal and spatial abilities; however this is almost entirely explained by their disadvantaged ... full story

Oct. 6, 2010 — Light drinking during pregnancy does not harm a young child's behavioral or intellectual development, a new study in the UK suggests. In fact, researchers found that children born to light ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.